Project Summary: Behavioral Optogenetics Core Optogenetic control of oxytocin release and mouse socio-spatial behavior is fundamental to this BRAIN Initative proposal on ?Oxytocin Modulation of Neural Circuit Function and Behavior?. Each Project requires optical identification of oxytocin neurons, optical activation or suppression of the oxytocin system, or other transgene expression for understanding the neural circuit basis of social behavior. A number of recent technical advances across levels now enable a deeper understanding of neuromodulation for flexible information processing and behavior in mice. Specficially, it is now possible to monitor and manipulate specific cell types (e.g., various inhibitory interneurons or subcortical modulatory systems including oxytocin), taking advantage of transgenic mouse lines combined with viral approaches for expressing opsins, fluorophores, pharmacogenetic constructs, or gene knockdown with shRNA. These transgenic and viral approaches in mice can be combined with imaging or intracellular recordings in behaving head-fixed mice, tetrode or photometry methods in freely-moving mice, or in brain slices for deeper understanding of the cellular and synaptic mechanisms of modulation and plasticity. Thus Aim 1 of this Behavioral Core is to breed and maintain valuable transgenic mouse lines, shared between Project labs (generally for cell-type specific manipulation of local circuits, certain receptor-expressing cells, or long-range modulatory projections). Aim 2 is to prepare these animals for Project team lab use via viral injection (mostly of opsins, DREADDs, or fluorescent reporters such as GCaMP6). This will greatly accelerate the studies performed by Project teams, as well as aid in troubleshooting and resource/reagent validation and replication across labs. Aim 3 is to work with team lab members to perform behavioral experiments. This is facilitated by incorporating this BRAIN Initiative Behavioral Optogenetics Core into the existing Rodent Behavior Core at NYU School of Medicine, augmenting the capabilities of that core facility to enhance the scientific environment throughout the institution.